I. Field
The present invention relates generally to communication, and more specifically to techniques for receiving data in a communication system with variable delay.
II. Background
Communication systems are widely deployed to provide various communication services such as voice, packet data, and so on. Each type of service may have different characteristics and requirements. For example, a packet data call is typically busty in nature but is often able to tolerate a variable amount of delay. Data packets may thus be transmitted whenever they are generated and based on the availability of system resources. In contrast, a voice call typically generates voice data continually within a range of rates and has a relatively stringent delay requirement.
A high-speed multiple-access communication system may be able to concurrently support different types of calls for different users. For a voice call, a terminal may receive voice data packets at regular time intervals, e.g., one packet every 20 milli-seconds (ms). However, the actual amount of time spent receiving a packet may be small (e.g., less than 1 ms) and may be just a fraction of the time interval between packets. The terminal typically does not know the exact arrival times of incoming packets due to various reasons such as the variable delay observed by these packets. In this case, the terminal may continually monitor the communication channel for incoming packets in order to ensure that all packets are received.
A terminal may be a portable unit (e.g., a handset) that is powered by an internal battery. For such a terminal, continual monitoring of the communication channel depletes battery power and shortens both the “standby” time between battery recharges and the “on” time for active communication. It is highly desirable to minimize power consumption, to the extent possible, in order to extend battery life.
There is therefore a need in the art for techniques for efficiently receiving data in a communication system with variable delay.